The idea of "open source" is incredibly important to
software developers, because it means that they can understand
how the technology works under the hood, down to every line of
code, then make their own improvements that they can submit to
potentially get included in the main project. It gives a single
developer the chance to make a huge impact on a popular piece of
software.

That's why announcement got the
loudest cheers at today's WWDC keynote, beating out a
new iOS, a new Mac OS X, and Apple's new music streaming
service.

I love that the WWDC announcement that got the most cheering and applause was the announcement that Swift is going open source

While a lot of early adopters
in the Apple app-developer world have had some success with
Swift, "open source is table stakes for consideration" for most
developers, says Stephen O'Grady, an analyst with developer
research firmRedMonk.

Because anybody can participate
in making an open source project better, they can attract
communities in the thousands dedicated to making that software
better.

For Swift, which still has a
long way to go before it can be considered fully featured and
ready to replace its decades-old forebears like Objective-C, that
can make all the difference in the world.

Plus, it means that developers
can repurpose the programming language to do whatever they want
with it. Before, developers were limited to using Swift to make
apps for iOS and Mac OS X.

Apple

"We think it would be amazing
for Swift to be on all your favorite platforms," Apple says in
a blog post
announcing Swift 2.0. Apple
also says "contributions from the community will be accepted —
and encouraged."

Now, developers can take the
source code and potentially use it for things like writing web
apps that run in the browser — which would actually put it
head-to-head with Google's Go programming language, which has
been open source since 2009.

"Swift going open source will remove an important obstacle
for some subset of potential Apple developers,"
says O'Grady.

How open is open?

There are still a few
questions, though.

A successful open source
community, like the kind Apple is trying to make with Swift,
doesn't just happen. Like any other community, there need to be
carefully enforced rules and procedures for decision-making, or
else mere anarchy is loosed on the world.

Apple simply can't integrate every line of code suggested by its
community into Swift. But the question of which code
it does accept from the community of dedicated
Swift fans is going to have a huge impact on the future of the
language. Too much, and Swift could start to lose its focus. Too
little, and Swift developers will feel left out and take their
talents elsewhere.

"There are also questions about how much control Apple will cede
to the broader community. Success will hinge on whether people
feel they can influence the direction of the language and tools,"
says Jonathan Karon, Senior Manager of Mobile Engineering at
New Relic, a company
that makes software to help developers monitor and maintain their
apps.

For instance, Google's Android is indeed released as open
source.

But the final versions, the versions that are released to
handset manufacturers, with all the cool new features? Those are
all Google. Developers can take that and do what they want with
it, but their changes very rarely make it back upstream to
Google.

This is why companies like Cyanogen, which makes its own
operating system derivative of Android, likes to say that they
have to "take
Android away from Google."

And while Apple has released software to open source
before, including some core bits and pieces of the Mac OS X
operating system, none of those open source releases have
attracted quite the same energized community as
Swift.

"In short, [releasing Swift to open source is]
a good move and one that will remove potential obstacles, but
questions remain in precisely how they govern the project moving
forward," O'Grady says.